i need to build a small data acquisition terminal in VB express 2008. it would be able to accept data packets on any serial port or USB virtual serial port. and to parse and send the data to excel.
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I am trying to write a thread safe application that contains 3 threads : -
1 - Data acquisition and decoding
2- Data graphing
3 - FFT and filtering
Thread 1 is collecting bytes from the serial port and converting them int integers (so taking two bytes) after is has captured 64 Bytes and converted into 32 integers, it then needs to pass the array to the graphing thread.
The graphing thread then plots the data and waits for more data.
Thread 3 also waits until thread one has collected 2023 integers and takes these and performs some FFT calculations (which take time).
My question is how do i share the arrays between the three threads without deadlocking the program? as the serial thread will be flying around reasonable fast (1000 bytes per second) so it will synclock onto the shared buffers for most of the time.
Originally i was going to use two synchronised queues, so when thread 1 has collected 32 bytes it queues the data into the graph queue, and once it has collected 2023 it queues the data into the FFT queue.
Then thread 2 and 3 can simple dequeue the data.
However using queues has the overhead of casting the data in and out, and as i know the data type i was planning on using two arrays :-
Dim GraphArray() as ushort
Dim FFTArray() as ushort
Then Thread 1 adds data to each thread, and thread 2 and 3 simple wait until the correct amount of data is available before removing the data. my question is there an array type that allows me to remove x amount of data from an array?
Because i cannot do this easily with the ararys defined as above (GraphArray, FFTArray), as i was planning on making them 1mByte and allowing thread 1 to fill them Knowing they should never overflow and then let thread 2 and 3 remove x amout of bytes at a time unless there is a better way of doing it
I had a copy of Visual Studio Professional on my old computer years ago, but decided against getting it on my new PC. Instead, I downloaded Microsoft's free offerings in the Express editions (C++, VB being the ones I am somewhat familiar with and interested in continuing).
I recently thought of an application that I would like to create, but am concerned that Visual Basic Express won't be able to handle it. I don't quite know what it means when 'they' say that Express can't work with remote data, so I will describe my application and let you tell me if I need to go ahead and get a pay-for version of VB.
a) USB temperature probe (like the one you used in high school chemistry, if you're young enough...) in fish tank, plugged into PC.
b) VB Express app intercepts the data stream and reads the temperature. (I can figure out numerical conversions if necessary using the Logger software which comes with the probe, and excel, if my VB application is showing numbers that follow a pattern with the temperature)
c) Application compares the temperature to the user-defined hi/low settings.
d) Application communicates wirelessly with an X10 Lamp Module, turning on or off the outlet, which is the same as turning on or off the 7.5 watt 'dumb' heater (no on/off switch; you plug it in to turn it on).I've seen ActiveX controls and code examples online that tell you how to code for X10 in visual basic)
Assuming there are some sensors interfaced to a microcontroller in a remote unit. And for the transmission of these signals, bluetooth is used for short range and GSM is used for long range.Now on the PC side for (LOW COST and GOOD) data acquisition, which module is required for the bluetooth and GSM respectively? and what's the algorithm to be used in each case?Also for testing purposes, if a cable is to be used which cable is appropriate?
View 3 RepliesI'd like to sample the data from the Arduino @ roughly 200Hz. Is there a more efficient way to do this than using a timer (which is what I am currently using)? Currently I am using[code]....
View 3 Repliesi have a sample code written in VB6 that allows communicating between different application windows and passes data. The link is below:[URL] I wonder how we can do the similar work inside VB.net. I simply claim a method between different applications communicating each other and transmits data. Lately i was using the old code and after my researchs on internet i also found different methods using System.Runtime.Remoting libraries
View 2 RepliesI am new for working with vb dot net. I have developed sample project with Ms.Access data base and some pictures I have a doubt on how to package. If you have answer ,sent me a step by step procedure. I have to some custom installation also.
View 1 RepliesWe are about to have a situation where our application needs to accept/give data to another application. Both applications are residing on the same machine.Two approaches being talked about are using a local web service that will do this or using files that will be used to share all of this data.
View 3 Repliesis there as simple way to pass data between 2 apps? it seems DDE support this, but vb.net 2010 seems not support DDE anymore. in my program, I need launch another exe, then wait the exe finish, and get the export data.
both apps are in the same solution. one method I can think of is: writing the data into a xml file, then load it from the main exe when the second exe is done.is there an easier way to do this?
Just wondering what is the simplest way to send data between ALL instances of my app on the SAME windows login on a single machine - I do not want to use anything that opens a port as i don't want there to be any chance of having it blocked by a firewall
View 3 RepliesI recently posted a WIA sample project in the codebank in this forum here : [URL] What I was trying to do is provide a video preview of the webcam video in a window, but I am having problems with trying to pass in the Window Handle. It should be as simple as Adding a reference to "WIAVideo 1.0 Type Library", and then putting in the following
[Code]...
i want to create a user control using WIA but i m get a error message at run time Error Assembly generation failed -- Referenced assembly 'Interop.WIALib' does not have a strong name. i m working of windows server 2003.
View 1 Replieswhere to find sample system with complete flow, database structure and data flow.. just for reference purpose.. system like inventory, payroll, accounting, billing and etc..
View 10 Replies what WPF based apps are?Is it an application that runs under Silverlight? If so, how?I know; Windows Forms based apps,console apps,DLL _ Class Library Projectsand I've had an introduction to ASP.Net.What I mostly want to know is, if WPF apps are for Silverlight then do they also run in a server based fashion like anASP.NET website would when you create ASP.Net webpages?Is it a way of creating what looks like a FORMS BASED application but it runs in a browser instead or what?Please enlighten me a bit further as I have no idea what WPF is all about.
I've been searching for hours tonight searching existing posts, other websites and all i can find are examples of how to capture a image from a webcam.Does anyone have any code that simple talks to the camera device via WIA, and then saves every image found on the device to a hard drive?I found this code below. Credit i cant tell you as i have a bunch of different flavors of code, but this only saves the file as a tmp file, and not the actual image file i expected after selecting?
Imports System.Drawing
Imports System.Runtime.InteropServices
Imports WIALib
[code].....
I created a sample ASP .NET app. I set the location to File System. When I tried to debug it I get an error message: "Internet Explorer cannot display this webpage". I was meant to understand that I can test this app. without Internet Connection. Why is it telling that?Only performance counts!
View 3 RepliesThis is the sample in C#
using System.Web.Script.Serialization;
var jss = new JavaScriptSerializer();
var dict = jss.Deserialize<Dictionary<string,string>>(jsonText);
Console.WriteLine(dict["some_number"]); //outputs 108.541
For I keep getting errors when I try to use an online converter to convert it to vb.net. Does anyone know how to rewrite this in vb.net?
The error I get from [URL] is: line 3 col 1: EOF expected
Is it possible to generate the sample xml(Used as Request xml for web service)from the xsd using vbscript code?
View 4 RepliesAnybody can tell em where can i get a com+ code sample (if it s ntier, better)?
View 5 RepliesI have found this code in the internet and I try it but it has an error. Here is the code that I get from the internet:
[code...]
i just trying to develop Dashboard application in vb.net but can't find any good example[not even in C#.net]..[either VB.NET or C#.NET and Doesn't using any third party control like VisiFire or etc] for dashboard style application.
View 1 RepliesI am a beginner VB.NET programmer, and I was hoping that there is a post that has a application that adds, edits, and deletes records from a Access database. Nothing fancy, just a simple interface to get me started.
View 1 RepliesI was wondering is there any sample programs to load & run within Visual Basic?
I've just installed VB 2010, & now I find no sample programs at all
Convert this solution from C# to vb.net? I'm not familiar to C#; It's a sample project that use DShow.net to capture video from webcam.[url]...
View 5 Replieswhere can I get vb.net sample master froms please?
View 1 RepliesI need to take a colour sample off of a window. So, given a window handle, and a coordinate, return the rgb color.
Can that be done via System.Drawing, or is that a straight API kind of task?
The sample program for the Chart Control is written in C#. It provides VB snippets but there appears to be a key piece of information missing or at least hidden. Can anyone explain to me what is needed to get the Chart Control working in VB.NET VS2008 Pro?Using the Chart Controls sample, I tried to create a RangeBar. The only thing showing is a big red X across the chart. Here's the code almost exactly as taken from the VB sample:
Private Sub ChartSample()
' Populate series data
chrtTCP.Series.Add("Tasks")
[code]....
As I am to VB.NET, I would like someone to help me on SearchButton code. I am using MS Access database. I would like to get the result of search commond into ListView.
View 3 RepliesI can retrieve the contents of a webpage into a variable like:x = objIE.Document.body.outerHTMLBut during development (data parse), Ikeep pulling up a live site and instead just want to store some sample html in a format that can be placed in a variable. The issue is that trying to directly place a raw html sample into a variable creates errors and would require going through and escaping quotes etc.
View 1 RepliesI downloaded some VB 2008 sample project from the net.Initially they seemed to run fine. But then they stopped running. They fall over when an attempt is made to connect to the northwind database. The error messge says something like "the sql or sql express and the northwind database has to be installed ". Which of course they are .
One possible reason that the code stopped working is that I tried to move the SQL on my Pc from one drive to another ( I moved it to another hard drive using cut and paste ). When I realise the Vb code had stopped working I simply reversed the above procedure, i.e cut and pasted back to the original drive.I think I should also add that there any different versions of sql on my PC, and I think the one that I cut and pasted is not the one used by the sample project.
